As per described on Week 7 (Sep 17 - Sep 20) Tuesday's list of activities, the PDMS was finally put into some molds and left to cure wrapped in aluminum foil at 70°C overnight. Only 5 molds were filled to test for shape and ease of retrieval. They will be retrieved on Tuesday morning. An updated version of the activities list is shown below.
Furthermore, if there is enough time throughout the week, some additional yet important tasks could be done.
New bottom layers were cut and PDMS molds were filled and left to cure overnight. It is expected that the molds will help the PDMS maintain a good shape for the substrate to completely seal the air chamber and prevent any leakages.
The PDMS substrates were retrieved. Upon 3 tests, the best way to remove them is to separate the piece from the walls of the cylinder mold using pointy tweezers. Then, when most of it has separated, push the substrate out.
The device was successfully fabricated. The PDMS substrate was slightly bigger than the hole, so there is some effort required to fit it inside the device. However, it can be done in a way that most of the surface remains untouched during the process, which will be further confirmed with modification experiments.
First, an issue must be addressed: the thickness of the middle layer, which gives height to the middle layer, is very small. With the insertion of the PDMS substrate, the surface ends up touching the internal face of the top layer, which can potentially damage the surface modification.
Flow reciprocation was achieved. To test for both leakages and reciprocation, the device was spun. If no sign of leakage was perceptible, the device was stopped and the recession of the fluid was observed.